1. Field of the Invention
The present invention generally relates to a headlamp for use on an automobile for example and, more particularly, to a headlamp comprising a reflecting mirror constituted by a free-curve reflector or a reflector known as a multi-reflector composed of a plurality of reflectors to form a light distribution characteristic by the reflector itself rather than by headlamp-lens cutting.
2. Background Art
Referring to FIG. 5, there is shown a prior-art headlamp 90 of the above-mentioned type by way of example of a multi-reflector. A reflecting mirror 91 of this headlamp 90 is constituted by a combination of an ineffective section 95 that does not reflect a light coming from a light source 92 and a main reflector 91a composed of a plurality of unit reflectors each providing an effective section that reflects the light coming from the light source 92. These unit reflectors have different orientations and light diffusion angles and are arranged on a rear portion of the reflecting mirror 91.
In the above-mentioned embodiment, a light distribution characteristic is provided by synthesizing the lights reflected from all unit reflectors. Therefore, in principle, a lens 93 need not be cut for obtaining the above-mentioned effect. This constitution provides an advantage that, if the surface of the lens 93 is tilted in agreement with vehicle contour, no distortion, such as a droop in both left and right ends of the light distribution characteristic, is caused. At the same time, this embodiment enhances the transparency of the lens 93 and the appearance of the headlamp 90 in its entirety.
However, in the above-mentioned prior-art headlamp 90, the light distribution characteristic is adjusted by the main reflector 91a composed of the plurality of the unit reflectors arranged on the rear portion of the headlamp 90. Consequently, the reflected light is blocked by a housing 94, thereby making it difficult to set a reflected light that travels in a direction largely diverging downward and sideways from the true front direction of the vehicle.
In addition, providing a large difference in reflected light travel direction between the adjacent unit reflectors forms a large difference in level between these adjacent unit reflectors. A light coming from the light source 92 and reflected from this large level difference is directed in a direction other than a desired direction, thereby causing a glare or the like. This makes it difficult to set a reflected light to travel in a direction largely diverging from the true front direction of the vehicle, resulting in a problem of making an area in front of and close to the vehicle darker, for example an area within five meters ahead of the vehicle.